I created a custom workflow via copy&modify of the OOB feedback workflow in SharePoint Designer 2010. When the workflow is started there are usually tasks created for every participant of the workflow in a task list.

After installing the workflow to a new server I've got the problem that the workflow won't create the tasks anymore. It starts but the tasks are missing.

Here's what I found out or tried so far:

When I first publish the workflow from SharePoint Designer and then try to start it for the first time, I get an error. It isn't very specific and just says that the workflow encountered an error; return to page bla bla. But if I try again to start the workflow, it suddenly works. This always happens if I publish the workflow again. Unfortunately I couldn't find any clearer logs on that so far.

After the workflow is started, I can go to the status page. There it says that the workflow has been initiated with the following participants and lists them.

I added another log - now with the verbose option - near the object reference error. There seem to be several other errors but I've got no idea if they have something to do with my workflow or where exactly they come from...
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JessicaApr 15 '13 at 17:54